U.S. patent number 6,261,298 [Application Number 09/506,532] was granted by the patent office on 2001-07-17 for device for concrement destruction or crushing.
This patent grant is currently assigned to Karl Storz-GmbH & Co. KG. Invention is credited to Klaus Irion, Wolfgang Leibersperger.
United States Patent |
6,261,298 |
Irion , et al. |
July 17, 2001 |
Device for concrement destruction or crushing
Abstract
A device for concrement destruction or crushing is disclosed
which comprises an elongate probe adapted to be introduced into the
human body, a drive unit that accelerates an impact body and a
lever unit comprising at least one single-arm lever which is
supported for rotation about an axis of rotation in such a way that
it bears, in its home position, on the proximal end surface of the
probe in particular, and which is rotated by the hitting impact
body such that the lever accelerates the probe, which bears
expediently against it, and the probe performs a translational
movement causing the destruction or crushing of the concrement by
the distal end surface of the probe hitting thereon. A distance
(r.sub.3) of the center of the bearing surface of the lever in its
home position on the proximal end surface from said axis of
rotation of the probe is shorter and preferably distinctly shorter
than the distance (r.sub.1) of the center of the impact area of the
impact body on the lever from the axis of rotation, and that the
ratio of the distances r.sub.1 and r.sub.3 is so selected that the
probe will reach a maximum translational speed with a maximum
transfer of energy from the impact body to the probe.
Inventors: |
Irion; Klaus (Liptingen,
DE), Leibersperger; Wolfgang (Tuttlingen,
DE) |
Assignee: |
Karl Storz-GmbH & Co. KG
(DE)
|
Family
ID: |
26051191 |
Appl.
No.: |
09/506,532 |
Filed: |
February 17, 2000 |
Current U.S.
Class: |
606/128 |
Current CPC
Class: |
A61B
17/22012 (20130101); B06B 1/12 (20130101); A61B
2017/00544 (20130101); B06B 2201/76 (20130101); A61B
2017/922 (20130101); A61B 2017/924 (20130101); A61B
2017/22014 (20130101) |
Current International
Class: |
B06B
1/10 (20060101); B06B 1/12 (20060101); A61B
17/22 (20060101); A61B 17/92 (20060101); A61B
17/88 (20060101); H61B 017/22 () |
Field of
Search: |
;606/128,127,107,167,19,22,902,170,171,184,185 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
35 37 155A1 |
|
Apr 1986 |
|
DE |
|
WO96/33661 |
|
Oct 1996 |
|
WO |
|
Primary Examiner: Philogene; Pedro
Attorney, Agent or Firm: St. Onge Steward Johnston &
Reens LLC
Claims
What is claimed is:
1. Device for concrement destruction or crushing, comprising
an elongate probe (1) adapted to be introduced into the human
body,
a drive unit that accelerates an impact body (2), and
a lever unit (4) comprising at least one single-arm lever which is
supported for rotation about an axis of rotation (5) in such a way
that it bears, in its home position, on the proximal end surface
(11) of the probe in particular, and which is rotated by the
hitting impact body such that the lever accelerates the probe,
which bears against it, and the probe performs a translational
movement causing the destruction or crushing of the concrement by
the distal end surface (12) of the probe hitting thereon,
characterised in that the distance (r.sub.3) of the centre of the
bearing surface of said lever in its home position on the proximal
end surface (11) of the probe (1) from said axis of rotation (5) is
shorter and particularly distinctly shorter than the distance
(r.sub.1) of the centre of the impact area of said impact body on
the lever from said axis of rotation (5), and
that the ratio of said distances r.sub.1 and r.sub.3 is so selected
that the probe will reach maximum translational speed.
2. Device according to claim 1, characterised in that the distance
r.sub.3 is longer than the spacing r.sub.2 of the centre of gravity
(10) of said lever from said axis of rotation (5).
3. Device according to claim 1 characterized in that said axis of
rotation (5) is displaceable along the longitudinal axis of said
lever in its home position such that said distances r.sub.1 and
r.sub.3 are adjustable.
4. Device according to claim 1, characterized in that the proximal
end of said probe and the drive unit are displaceable relative to
each other in a direction orthogonal on the longitudinal axis of
said probe such that the lever ratios are adjustable.
5. Device according to claim 1, characterized in that said lever
element has a cross-section varying over its length.
6. Device according to claim 1, characterized in that the mass
(m.sub.2) of said lever corresponds approximately to half the mass
(m.sub.1) of said impact body or less, and that the mass (m.sub.3)
of said probe amounts to roughly twice the mass of said impact body
or more.
7. Device according to claim 6, characterised in that the following
relationship applies, at least in approximation, for said distances
r.sub.1 and r.sub.3 :
wherein
m.sub.1 mass of the impact body
m.sub.3 mass of the probe.
8. Device according to claim 1, characterized in that said drive
unit comprises a tube (3) in which said impact body (2) is
accelerated.
9. Device according to claim 8, characterised in that said impact
body (2) is accelerated in said tube (3) by means of compressed
air.
10. Device according to claim 8, characterised in that said impact
body (2) is electromagnetically accelerated in said tube (3).
11. Device according to claim 1, characterized in that said drive
unit comprises at least one additional lever.
Description
DESCRIPTION
1. Field of the Invention
The present invention relates to a device for concrement
destruction or crushing in accordance with the introductory clause
of Patent claim 1.
2. Prior Art
Devices for intracorporeal operation for concrement destruction or
crushing have been commonly known. Such devices are used, for
instance, as so-called lithotripters in medicine for destroying
concrements such as renal calculi, urinary calculi or the like by
short surge pulses of a probe introduced into the human body, or to
comminute them to such a size that they can be discharged via the
urinary tract.
A device which the wording of the introductory clause of Patent
claim 1 starts out from is described in the document WO 96/33661.
That device comprises an elongate probe adapted for being
introduced into the human body, particularly via the ureter. A
lever bears against the proximal end of the probe, which performs a
rotating movement for accelerating the probe to perform, in its
entirety, a translational movement at a sufficient rate such that
when the distal end of the probe hits the concrement the latter
will be crushed. The lever is driven, for instance, by means of an
impact body which hits the lever with a high speed for driving it
to perform a high-speed rotational movement.
From the European Patent EP 0 317 507 B1 an apparently similar
device for concrement crushing is known. In that device a
projectile hits the proximal interface of a wave It is intended
that the hitting projectile should excite shock waves in the wave
guide which are meant to result in a displacement of the distal
interface of the wave guide.
In distinction from the device known from the European Patent EP 0
317 507 B1, the device known from the document WO 96133661, wherein
merely or mainly shock waves or compression waves are excited in
the wave guide, presents the following advantage: as with the
device known from WO 96/33661 the probe is displaced as one unit
the entire mass of the probe contributes to the kinetic energy of
the probe. In the device known from the European Patent EP 0 317
507 B1, by contrast, only that fraction of the entire mass
contributes to the kinetic energy which is influenced by the
compression wave "migrating therethrough". As a result, the
"effective kinetic energy" is much higher in the device known from
WO 96/33661, where the probe is moved as a complete unit, so that
an excellent crushing result is achieved.
The reason for the translational movement of the probe as a single
unit, instead of the excitation of a shock wave or a compression
wave, resides in the use of a lever:
The lever produces the effect of a transformation element achieving
a low-pass effect. Due to this low-pass effect the kinetic energy
of the impact body is transformed by the lever, which serves as
transformation element, in such a way that substantially only a
translational or uniform straight movement of the probe is achieved
with the aforementioned high kinetic energy, without a
therapeutically effective compression wave fraction.
BRIEF DESCRIPTION OF THE INVENTION
The present invention starts out from the finding that with an
optimisation of the ratio of the distance of the bearing surface
centre of the lever, which serves as transformation element in a
home position on the proximal end surface of the probe, from the
rotational axis, to the distance of the centre of the impact area
of the impact body on the lever from the rotational axis it is
possible to achieve a translational speed as high as possible at an
optimum kinetic energy of the probe.
In particular, the present invention is based on the finding that
in the device known from WO 96/33661 the lever ratios--as shown in
the drawing--are not selected at an optimum.
The present invention is therefore based on the problem of
proposing a device serving for mechanical concrement crushing,
wherein the probe hits on the concrement at the maximum speed
possible and wherein a maximum amount possible of kinetic energy of
the impact body is transferred to the probe.
In accordance wit the invention, this problem is solved with the
provisions that the distance of the centre of the bearing surface
of the lever in its home position on the proximal end surface of
the probe, from the rotational axis is smaller and particularly
definitely smaller than the distance of the centre of the impact
area of the impact body on the lever from the rotational axis, and
that the ratio of the distance is so selected that the probe will
achieve a maximum translational speed.
This means that the first impact point is located between the
rotational axis and a freely mobile end of the lever arm, and that
the probe is acted upon in particular by another area of the lever
element rather than by the centre of the lever element. Whereas in
the conventional lever design and lever arrangement, which are made
in consideration of the cylindrical structure of the housing, the
first impact point is provided on the freely mobile lever end and
the second impact point is located precisely in the middle between
the two lever ends, the inventive asymmetric position of the impact
points permits the matching of the energy transfer from the impact
body to the probe with the involved masses of the impact body, the
lever and the probe, and makes it possible that losses in energy
transfer, which are caused by the lever mechanism, will be largely
avoided.
The lever may not only be a single-arm lever but fundamentally the
most different types of transfer or transformation elements such as
the arrangements of several levers may be selected which, due to
different distances between the impact points and the rotational
axes, i.e. on account of different impact radii, allow for matching
the lever action with a maximum energy transfer to the impact
probe.
With the optional application of a single-arm lever it is preferred
that the distance of the centre of the bearing surface of the lever
on the proximal end surface of the probe is wider than the distance
between the centre of gravity of the lever and the rotational
axis.
In particular, the rotational axis may be provided for displacement
along the longitudinal axis of the lever in its home position so
that the lever action can be adjusted. For an optimisation of the
energy transfer not only in the zone of the interior of the housing
but also between the distal probe end and the concrement a
regulation of the lateral position of the lever element is
expedient when the energy transfer for crushing concrements of
different sizes should be harmonised with the respective concrement
mass.
In an alternative or additionally it is possible that the proximal
end of the impact probe and the impact unit are provided for
lateral displacement relative to each other so as to permit a
regulation of the lever action. Whilst a displacement of the lever
varies both impact radii it is possible, in correspondence with
this potential configuration, to optimise one of the impact radii
independently of the other radius. In this context, the term
"displacement" is to be understood here to denote any movement
which results in a lateral dislocation of the probe and the impact
unit, in opposition to the literal meaning otherwise common; for
instance, a rotation of the impact unit or of the rear part of the
housing, respectively, about an axis extending outside the centre
of the housing or the proximal probe end, or any other adjusting
mechanism may result in a lateral approximation of the impact unit
and the impact probe (or their extensions on the housing side,
respectively).
It is moreover possible that the lever element has a varying
cross-section over its length. With this provision it is
possible--either as an alternative of or in addition to the
aforementioned provisions--to achieve a further matching of the
energy transfer to the lever and from the lever to the probe.
Particularly when the mass of the lever is definitely smaller than
the mass of the impact body and the mass of the lever corresponds
roughly to half the mass of the impact body or less and the mass of
the probe corresponds to twice the mass of the impact body or more
approximately it is preferable that the following relationship
applies for the distances r1 and r3, at least in approximation:
wherein
m.sub.1 mass of the impact body
m.sub.3 mass of the probe
r.sub.1 distance of the centre of the impact area of the impact
body on the lever from the axis of rotation
R.sub.3 distance of the centre of the bearing surface of the lever
in its home position on the proximal end surface from the axis of
rotation of the probe.
With this configuration the kinetic energy of the projectile is
transferred to the probe practically completely, despite different
masses of the probe and the impact body. As due to its length which
is necessary for introduction into the human body the probe has
mostly a distinctly heavier weight than the projectile a complete
energy transfer can be achieved only with different impact radii of
the impact unit and the probe.
On account of the lever speed which is proportional to the length
of the lever arm, the aforementioned condition for the ratio
corresponds to the energy preservation or the complete energy
transfer to the probe, with the mass of the probe including, in the
true sense of the word, also the masses of all parts that are moved
during the impact process simultaneously with the probe.
In all other respects, the inventive device may be configured in
the same manner as the unit described in WO 96/33661:
For instance, the drive unit may include a tube in which the impact
body is accelerated, e.g. by means of compressed air or by means of
solenoids.
Moreover, the drive unit may include at least one additional
lever.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be described in the following by exemplary
embodiments, without any restriction of the general inventive idea,
referring to the drawing which explicit reference is made to in all
other respects as far as the disclosure of all inventive details is
concerned which are not explained in more details in the text. In
the drawing:
FIG. 1 is a schematic of an inventive lithotripter,
FIG. 2 is a graphic illustration of the energy transfer which can
be achieved with conventional lithotripters for different probe
sizes,
FIG. 3 is a graphic illustration of the energy transfer which can
be achieved with the inventive lithotripter for different probe
sizes, and
FIG. 4 is a graphic illustration of the energy transfer which can
be achieved with the inventive lithotripter for different impact
radii of the probe.
DESCRIPTION OF AN EMBODIMENT
FIG. 1 shows an inventive device. The device comprises a probe 1
that may be introduced, for instance into the ureter, and which
serves to destroy or crush a concrement in the body such as a
urinary calculus. As is known from the document WO 96/33661, the
probe is accelerated to a translational speed, which amounts to
5-10 m/s in a typical case, in the following manner:
An impact body 2 is accelerated in a tube 3, for instance by means
of compressed air or by an electromagnetic field, to a
comparatively high speed. The impact body 2 hits on a lever 4 which
is rotatable about an axis 5 and which, in its home position, bears
against the proximal end of the probe 1. The axis of rotation 5 is
spaced by a defined distance by a holder 9 e. g. on the outside
wall 8 of a handpiece.
The projectile 2, which is accelerated by the impact unit 3, hits
against the lever 4 which acts upon the proximal end of the impact
probe and thus transfers the kinetic energy of the projectile to
the probe. With the lever, which has the function of a
transformation element, a low-pass effect is achieved so that
ultrasonic compression waves will not be excited. The probe rather
performs practically a pure translational movement with a high
kinetic energy, without the excitation of therapeutically effective
compression waves in the probe. Insofar, the device is known from
the document WO 96/33661.
r.sub.1 denotes the distance between the centre 6 of the impact
area of the impact body 2 on the lever 4 and the axis of rotation
5.
r.sub.2 indicates the distance between the centre of gravity 10 of
the lever 4 and the axis of rotation 5.
r.sub.3 denotes the distance between the centre 7 of the bearing
surface of the lever 4 in its home position on the proximal end
surface 11 of the probe 1 and the axis of rotation 5.
In accordance with the invention, the ratio between the distances
r.sub.1 and r.sub.3 is so selected that the probe will reach a
maximum translational speed at a maximum of kinetic energy.
To this end the first impact point 6--in opposition to the device
known from the aforecited prior art document--is not disposed
directly on the freely mobile--in FIG. 1 lower-end of the lever;
moreover the second impact point 7 may be arranged at an asymmetric
offset in particular.
It is particularly preferable that the distance r.sub.3 is longer
than the distance r.sub.2 of the centre of gravity 10 of the lever
from the axis of rotation 5.
FIGS. 2, 3 and 4 illustrate the energy transfer conditions which
can be achieved with known and inventive devices for intracorporeal
lithotripsy.
FIG. 2 illustrates the energy transfer i.e. the ratio of the
kinetic energy transferred by the impact probe relative to the
energy of the projectile hitting on the lever, for probe masses
m.sub.3 from twice to five times the mass m.sub.1 of the
projectile. Due to the lever mechanism of the conventional device,
which is matched with the cylindrical shape of the housing, the
kinetic energy of the projectile is transferred to the probe only
incompletely even in the most favourable case of a probe weight of
roughly 67% of the projectile mass.
FIG. 3 shows the energy transfer situation with the inventive lever
mechanism for the same probe sizes, wherein the first impact radius
r.sub.1 is optimised for the mass ratio between the projectile and
the lever whilst the impact radius r.sub.3 is optimised for a probe
having twice the weight of the projectile; in the case of a lever
having a mass corresponding to half the mass of the projectile, for
instance, both impact radii are shorter than half the length of the
lever; as the probe is heavier than the projectile the impact
radius r.sub.3 is smaller than the impact radius r.sub.1.
FIG. 4 shows the energy transfer as a function of the ratio of the
impact radius r.sub.3 to the impact radius r.sub.1 with a first
impact radius harmonised with the mass of the lever and with a
probe having a mass twice the weight of the projectile, which
reaches the maximum value of 1 like in FIG. 3.
From FIGS. 2 to 4 it is apparent that the asymmetric arrangement of
the impact unit and the impact probe, which is proposed in
accordance with the present invention, permits a practically
complete transfer of energy to the impact probe relative to the
lever, which cannot be achieved with conventional lithotripters
provided with a lever mechanism, so that the efficiency of
lithotripters in concrement crushing will be increased.
* * * * *